In recent years, a film capacitor mounted on electric equipment, electronic equipment, industrial equipment, automobiles, or the like has been required to enhance reliability of the film capacitor by dissipating heat generated during charge and discharge.
For example, Unexamined Japanese Patent Publication No. 2013-26586 discloses a film capacitor which includes a plurality of capacitor elements and a bus bar connected to the capacitor elements. The film capacitor is provided with heat dissipation means disposed at a portion closest to a terminal for external connection that is provided at the bus bar, which is excellent in heat dissipation performance as compared with the other portions. The film capacitor is specifically described below.
FIG. 6 is a perspective view showing a configuration of a conventional film capacitor, and FIG. 7 is a plan view of the film capacitor in a state in which positive electrode bus bar 92A on an upper surface side is excluded. The film capacitor houses a plurality of capacitor elements 91, positive electrode bus bar 92A, and negative electrode bus bar 92B in case 93. Metallikon electrodes formed on both ends of each capacitor element 91 are respectively connected to positive electrode bus bar 92A and negative electrode bus bar 92B. Also, the conventional film capacitor is configured so that no capacitor element 91 is disposed at a portion closest to positive electrode external terminal 92A2, which is provided at positive electrode bus bar 92A for external connection, and negative electrode external terminal 92B2, which is provided at negative electrode bus bar 92B for external connection. The film capacitor is configured so that only mold resin 96 is disposed at the portion. Even when heat is conducted together with current applied from an input side to positive electrode external terminal 92A2 and negative electrode external terminal 92B2, this heat is first conducted to mold resin 96 before the heat is conducted to capacitor elements 91 from positive electrode external terminal 92A2 via positive electrode bus bar 92A and negative electrode external terminal 92B2 via negative electrode bus bar 92B, respectively. Accordingly, the heat can be dissipated from this mold resin 96 to outside. Hence, in the conventional film capacitor, large heat conduction which causes damage to capacity elements 91 can be suppressed.
In this way, heat generation can be suppressed to some extent in the conventional technique disclosed in Unexamined Japanese Patent Publication No. 2013-26586. However, a film capacitor further improved in heat dissipation performance has been required in recent years.